A196000 Numbers k such that 90*k + 19 is prime.

0, 1, 2, 4, 8, 9, 10, 11, 14, 16, 17, 22, 23, 24, 25, 28, 30, 34, 35, 36, 39, 41, 43, 46, 48, 50, 53, 55, 56, 60, 63, 64, 65, 69, 74, 77, 78, 79, 80, 81, 83, 85, 86, 91, 93, 98, 99, 101, 102, 107, 108, 109, 111, 112, 115, 116

Offset: 1

Author

J. W. Helkenberg, Oct 27 2011

Keywords

• nonn
• easy

Comments

A142322 is a digital root 1 and last digit 9 preserving sequence.

Links

• Ivan Neretin, Table of n, a(n) for n = 1..10000

Crossrefs

Cf. A195953, A181732, A198382.

Programs

Maple

A142322 := proc(n)
        option remember;
        if n = 1 then
                19 ;
        else
                a := nextprime(procname(n-1)) ;
                while (a mod 45) <> 19 do
                        a := nextprime(a) ;
                end do;
                return a;
        end if;
end proc:
A196000 := proc(n)
        (A142322(n)-19)/90 ;
end proc:
seq(A196000(n),n=1..80) ; # R. J. Mathar, Oct 31 2011

Mathematica

Select[Range[0, 120], PrimeQ[90 # + 19] &] (* Ivan Neretin, Apr 27 2017 *)

PARI

is(n)=isprime(90*n+19) \\ Charles R Greathouse IV, Apr 25 2016

Formula

a(n) = (A142322(n) - 19)/90.